Suction regulating valve



May 12, 1953 w. D. TEAGUE, JR 2,638,107 SUCTION REGULATING VALVE Filed April 5, 1948 IN VEN TOR.

lL/IIL'TER D. TEHEUEJB.

Patented May 12, 1953 Walt r 1), Teams. Jr" Alpine, 1., assigns! to Bendix Aviation dlorporation Fllcterboro, N. .L, :1 corporation of Delaware Application April 5, 1948, 'SeriallNo. 13,051

19 Olaims.

The present application relates to "an improved suction regulating valve for enairomft instnu ment suction line.

It is common practice to pnovlde a suction line foruse in the operation of inflatable ice eliminab log units on ei-remit, .as shown foraexazmp'le, in the copending application Serial No. 498,248, filed August 11, 1943, by Donald M. Lawrence, Myron L. Taylor and David Gregg and assigned to Bendix Aviation Corporation, now Patent No.

Moreover, many aircraft instruments, such as the directional g ro, gyro horizon and turn indi caton, are air driven, and it is common to induce atmospheric air into the casing of each of these instruments directed at the conventional buckets orned onthe rim of the euro motor and to exhenst thee-1r at a definite suction pressure, so that the gums may be spun with sufficlent sneer! to marry out their :difl erent indicating or control functions. Suction is usually applied to the exhalust of the instrument casing by means of a vacuum pump, which is usually driven directly from the engine.

It is common practice to provide in such suction lines, a regulating valve to damp out fluctuations the suction line pressure and to maintain anredetermined difierential between the $311105 phcric pressure and the pressure in the suction line. as shown for example in U. 3. Patent .No, ,151,531, granted June 6, 119319, to G. V. Rlflsky, and U. s. Patent No, 2,194,749, granted March 26. 1944!, to David Greggboth of whieh patents have een assigned to Bendix Aviation Corporation,

For most'purposes as described above, a corn out difierentia-l regulator is suificient control. However, on aircraft designed for high altitude peration. e constant differential results in on increasing pressure ratio as altitude increases.

Thus,'for example, a regulator may be designed to hold fiveinches of mercury differential pressure; At sea level, the pressure may be approximately 30 inches of mercury so thatthe suction pressure would then be 25 inches of mercury. This corresponds to a pressure ratio of 1.2tol. However, at .anaaltltude vcorreepending to a pressure of teninches of mercury the *difierential suction pressure may he "five inches of mercury corspondin to a pressure ratio of 2 to l.

The vacuum pumps which supply the suction are generally-limited in the compression ratio which they s will withstand. With the desired Pressure difiegentja l uforenoted, this oritioal eonspression retiomay be reached before the mess um altitude of Q329 attaine An object of the present inven on, monotone. is to m'ovidc e zpreesuse regulating valve may be used in the-suction line with the nmtven tionel diffenential museums regulating valve to of the aircraft instruments or infletableiceelimb prevent a predetermined critical pressure "natic from being exceeded at theseme time retain some degree of fiifiexentiol pressure for emotion noting elements at the higher altitudes of aircraft.

Further, .an object of the present invention is v o provide such suction regulating valve .rcspon' sive to etmossherio pressure and suction line presses-e to maintain at high altitudes the smtion line messurc :at a predetermined ratio of the prevailing atmospheric pressure and time more effectively mevcnt overloading of the vacuum pump.

Another object of the invention is t om ide a cylindrical gate valve for controlling the su tion ne pressure which Valve forms e p rt of an air motor piston operated loy dlflereno in atmospheric pressure and controlled suction line pressure.

Another object of the invention is to provide a novel suction line control mechanism having a control piston open at one side to atmospheric pressure, and a controlled valve passage etwe n the other side of the control piston and the suction line pressure, while "an atmospherio-suction line pressure responsive bellows controls the valve passage to afiect said control piston so as to maintain the suction line pressure at a predetermined ratio of the atmospheric pressure.

Another object of the invention is to provide a novel bellows arrangement for controlling the aforenoted mechanism in which there are proid d s pair of different sized bellows aflfixed at opposite sides to a summon supportin Plate and v in which the opposite movable ends of the bellows are connected together by a tie bolt so that the ends of the same will move togethen Dne of the bellows is responsive to atmospheric pressure and the other is resp nsive to suction line pressure. while the interior of the bellows is evacuated so that the be lows provide a ratio effect which is dependent upon the ratio of the surface areas of the two bellows. i

Another object of the invention is to provide a.

novel bellows assembly to position a pilot valve s to regulate a main valve so as to provide u predetermmed pressure ratio between'stmospherio pressure and a suction impr ss within the operstine range of the main valve.

-h' e above and other objects and tea-tunes of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing, wherein one embodiment of the invention is illustrated by way of example.

The drawing is a sectional view of a suction regulating valve embodying the invention.

Referring to? the'. drawing, there is provided a suction conduit I having one end connected through a suitable conduit to the casing of the aforenoted air driven aircraft instruments. The opposite end of the conduit 1 is connected to the input of the suction pump. v N

Opening into the suction conduit 1 is a nozzle 2 formed a part of the conduit l. The nozzle 2 includes an annular portion having a flared surface which rises progressively from a circumferential edge 6 to a point 8 and then progressively descends into an annular orifice to form the sink-like nozzle 2. a

"A castingv 12 formed integral with the suction conduit -lsurrounds the nozzle'2 and has suit-- ableopenings l3 formed therein to permit the flow of air from the atmosphere to the nozzle 2. The openings !3 are covered by a suitable screen l4. A lower casing portion l fits about the casting 1 2- and has provided therein openings [6 which coincide with openings E3. The casing l 5 is suitably fastened to the conduit I.

Mounted at the upper end of the casting I2 is a plate it which fits within the casing i5 and from which projects a member 26. Slidably mounted on" the. member 26 and longitudinally movable thereon is a cylindrical gate valve 22 having a knife like edge 23 which is adapted to contact theisurface of the nozzle 2 at an acute angle so as to" control theflow of air into the suction conduit I.

Ihe diameter of theknife edge 23 is substantially the same as the diameter of member 26, thus balancing valve 22 and eliminating the efiectof "changing pressure in conduit I on the action of'the valve.

Affixed to the cylindrical gate valve 22 is a servo piston member 24 formed integral with the cylindrical gate valve 22'and providing a'servo' motor means for operating the valve 22.

"The-surfaceof the underside of the piston 24 isf-s'paeedfrom thesurface of the nozzle 2 and inclined s'oasto cooperate with the surface of the nozzle 2 for the full rated flow of air upon the cylindrical valve 22 opening the nozzle 2. The surface-of the underside of the piston 24 issufliciently spaced 'from the surface of the nozzle proper for such flow and with the area normal tothe air stream progressively decreasing from the outer circumferential edge 6 to the inner annular orifice so as tosmoothly accelerate the airflow from the circumferential edge 6 into the suction conduit I. 4' I The piston 24 is slidably mounted in a chamv her- 26 formed in the casting l2 and the piston 24 loosely fits therein so as to permit limited lealrageof atmospheric pressure into the chamber 26 fro 'mgthe underside of the, piston 24. A spring 28 is interposed between'thepiston member 24 and the plate I8 so as to bias the piston 24 and the cy indrical gate valve 22 in a direction to'-' wardsthe nozzle 2.;

It: will be-seen then that atmospheric pressure git gthrough openings i3- 'l 6 "biases the piston 28 1 chamber- 26 defined 'by the casting l'l'plate l8 and piston'22. w 4

jdi rection' opposing the force of the spring At the" opposite sideof the piston :24 is the- The plate l8 has formed therein a port 36 aligned with a valve port 32 formed in a plate 34 positioned in the casing l5 adjacent the plate I6 and forming a bottom plate for a second chamber 36 immediately above the chamber 26.

The port 32 opens through port 36 into the member 20 and through ports 38 into chamber 26. Slidably mountedin the-member 201' is a servo valve 39 which controlsthe valve port 32 and is biased by a spring 41 in a direction for closihg valve port 32. The valve 39 has a projecting part 43 extending into the chamber 36 and ar ranged for actuation by a bellows mechanism indicated generally-by the numeral 45. The foregoing servo mechanism is of the general type disclosed in the copending application serial No. 524,063, filedFebruary 26, 1944, by Walter D.

Teague, Jr. and assigned to Bendix Aviation Corporation.

The chamber 36 is defined by the bottom plate 34, a top plate 4'! and a liner 48 positioned withpressure.

Mounted on the plate 4! and extending into the chamber 58 is a flexible resilient bellowsi 60..

which provides one pressure responsive element of the bellows mechanism 46.

The inherent re,. silience of bellows 60 in the position shown tends -to collapse the bellows 60.

Mounted at the opposite side of the plate 41 and extending into the chamber 36 is a flexible resilient bellows 62 which has a greater surface extend the bellows 62 The interior of the bellows 60 opens into theinterior of the bellows, 62 through an opening 64 formed in the plate 41. The interior of the bellows 60 and 62 is evacuated.-

The bellows 60 has a movable end 66 whichis'} connected to a movable end 61 of the bellows 62 through a rigid hollow rod 68 that passes through the opening 64. A stop 16 provided on the-rod' "68 is arranged to engage plate 47 to limit the collapsing of bellows 62 under the fluid pressure" acting on the surface area of bellows 62.

Screw threadedly engaged in the hollow rod 68 is a second rod 12 having a lower end portion calibration of rod 12 relative to the projecting part43 of valve 39.

The position of rod 12 is adjustable so that,

it, may be so calibrated that; member 14 will to conduit and at ports 86and as into the and formed in casting .l2 and casing'l5.

chamber 36.

It will be seen then that innormal 'operation'-- the bellows 62 havingthe'greater surface 'a'rea .H will be subject to the pressurein the suction? e nduit I hile-op osing the contraction-tr the 5. bellows 62 is the bellows Gil subject to atmos pl-ii io pressure.

upon the pressure the suction conduit r decreasing so as to exceed a predetermined raas relative to atmospheric-pressure, the atmospheric pressure acting on bellows 6'9 will tend to collapse bellows 6t and the lower pressure acting onbellows 62- will tend. to permit bellows B2 to expend until the member M actuates the valve 39 to open valve port 32, whereupon suc tio'napp'lied through port as to chamber will cause piston 24 under atmospheric pressure at the lower side to cause the cylindrical gate valve 22 to open nozzle 2 so as to: increase the pressure in conduit it The increase in the pressure in conduit I will then tend to collapse the bellows 62 whereupon the servo valve 39 closes.

Leakage of atmospheric pressure into chamber 25 through the loose fit of piston 24 in chamber 26, together with the biasing force of spring 28 will then tend to move the piston '24 and cylindrical gate valve 22 to a closed position uiitil the foregoing o eration is repeated.

It will be seen from the foregoing that there is provided a novel regulator valve including a pair of bellows Eli-$2 to e'fiec't a predetermined ratio between the pressure in the instrument suction line and the prevailing atmospheric pressure; The ratio of the surface areas of the two bellows will determine the ratio to which the valve mechanism will regulate. In the latter mechanism, the bellows assembly positions a servo pilot valve 39 and hence a main regulator valve 22, to maintain the pressure in the suction conduit I at a value proportional to and less than the atmospheric pressure at altitudes in excess of that for which the conventional differential pressure control is designed for use.

Thus in the event the altitude of the aircraftis not excessive, the conventional differential pressure regulator valve in the suction line may maintain the predetermined desired differential pressure. However, upon the altitude of the aircraft exceeding a predetermined value whereupon the ratio of the pressure in the suction conduit tends to exceed a predetermined safe ratio for operation of the vacuum pump. then the pressure ratio regulating valve of the present invention will come into operation so as to prevent the pressure in the suction conduit I from decreasing below a predetermined pressure or value proportional to that of the atmo'sphere which value the vacuum pump may maintain without damage, at the higher altitudes.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts may be made to suit requirements.

What is claimed is:

'1. A fluid pressure regulating mechanism, comprising, in combination, a suction conduit, a nozzle formed integral with and opening into the conduit, a housing formed integral with said conduit and surrounding said nozzle, said housing having openings formed therein communicating said nozzle to atmosphere, a cylindrical gate valve for controlling said nozzle, means closing the interior of said cylindrical valve to fluid passage, said nozzle arranged as a valve seat for cooperating with said cylindrical gate valve, a piston formed as a part of said valve and having a surface at one side spaced from the surface of siv'ly decreasing from the openings in said housmg to the edge of the nozzle so as to smoothly accelerate the air flow from the atmosphere n to said suction conduit, and means for controlling the application of pressure from the suction conduit to the other side of said piston for opening and closing said cylindrical gate valve.

2. The combination defined by claim 1 includ ing spring means for biasing said cylindrical gate valve in direction to close said nozzle against the atmospheric pressure acting at the one side of said piston.

3. The combination defined by claim 1 in which said control means includes a mechanism responsive. to atmospheric pressure and the pressure in said suction conduit to control the application of the suction conduit pressure to the other side of the piston.

4'. The combination defined by claim 1 in cluding a first chamber subject to atmospheric pressure, a second chamber subject to the suc' tion conduit pressure, plate dividing one chamber from the other, a first bellows projecting from one side of the plate into the first chamber, a second bellows projecting from the other side or the plate into the second chamber, each or said bellows having a movable end and said second bellows having a greater surface area than said first bellows, a rod passing through said plate and operatively connecting the movable end of one bellows to the movable end of the other bellows, a port to open said second chamber to the other side of said piston, a valve member to open and close said port, and said first and second bellows arranged to regulate said valve member in response to atmospheric and suction conduit pressures to position said cylindrical gate valve so as to effect a predetermined ratio between the atmospheric and suction conduit pressures.

5. A pressure regulator for use in a suction line between a vacuum pump and an aircraft device comprising, in combination, a suction conduit, a cylindrical casing on said conduit, said casing being partitioned into a plurality of chamhers, a gate valve in the suction conduit for bleeding air into said conduit, differential bellows means, one of said chambers open to said suction conduit, a piston responsive to atmospheric pressure slidably mounted in an adjacent chamber to actuate said gate valve, a servo-valve protruding into said first-mentioned chamber, said servo-valve actuated by the movement of said bellows to open said first chamber to said adjacent chamber to effect movement of said piston in a direction to open said gate valve to bleed air into said conduit.

6. The combination defined by claim 5 in which said bellows means include. a bellows in one chamber responsive to atmospheric pressure, and an inline bellows attached thereto in an adjacent chamber responsive to suction conduit pressure, and a common rod through said first and second mentioned bellows axially actuated by the differential pressure thereof.

7. The combination defined by claim 5 in which said gate valve in the suction conduit for bleeding air into said conduit includes a cylindrical knife-edge gate valve for regulating the flow of air into said suction conduit.

8. A pressure regulator for use in a suction line between a vacuum pump and an aircraft device, comprising, in combination, a suction conduit, a valvein said conduit for bleeding air into said conduit, control means foroperating said bleed valve including a servo piston operatively connected to said bleed valve, a servo said bleed valve to maintain the pressure insaid suction conduit at a predetermined ratio proportional to and less than ambient atmospheric pressure.

9'. A pressure regulator for use in a suction line between a vacuum pump and an aircraft device, comprising, in combination, a suction conduit, a valve in said conduit for bleeding air into said conduit, control means for operating said bleed valve including a first bellows responsive to changes in ambient atmospheric pressure, a second bellows having a predetermined greater efiective area than said first bellows and responsive to the pressure in said 'suction conduit, said second bellows having a predetermined greater efiective area than said first bellows, a servo valve operated by the first and second bellows, a servo piston operated by the pressure differential between ambient atmospheric pressure and the pressure in said suctionconduit, said servo piston forming a part of saidbleed valve, and said servo valve being operated by said first and second bellows to control the application of the pressure in said suction conduit to said servo piston to thereby vary the position of said bleed valve and maintain the pressure in said suction conduit at a predetermined ratio proportional to and less than ambient atmospheric pressure.

10. The combination defined by claim 9 in which said bleed valve includes a cylindrical knife edge gate valve for regulating the flow of air into said suction conduit.

WALTER D. TEAGUE, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 143,345 Harrington Sept. 30, 1873 312,724 Jarboe Feb. 24, 1885 1,929,198 Crawford Oct. 3, 1933 2,161,531 Rylsky June .6, 1939 2,208,554 Price July 16, 1940 2,400,048 Jones May '7, 1946 2,425,000 Paget Aug. 5, 1947 FOREIGN PATENTS Number Country Date 335,044 Great Britain Sept 18, 1930 

